Why is someone full of hope hopeful not hopefull?

The suffix has one “l” in all its uses, i.e., wonderful. Just one of those quirks of the English language where the suffix, being an adjectivial suffix, is different from the word by itself. It does not mean “full”, it means “full of”; a subtle difference in meaning.

@zenvelo (edited out) My error.

While there is a difference in meaning, however subtle, the latter spelling is only used when transcribed as two words: __hope full._

When standing alone, the suffix has two l‘s. Check the Oxford English Dictionary.

When would one ever use “hope full”? Suffixes do not stand alone, do they? “Hopeful” means “full of hope.”

That’s just how it is spelled. English is a nightmare. You just memorize what you need to.

87% of English words are spelled phonetically. This is why teaching Phonics makes so much sense.

So to answer your question “do we just memorize…them all”

For that 13% the answer basically is YES.

I’m not sure what the ALL in your question consists of. But we don’t need to memorize All the words individually, just that small percentage which does not follow phonetic rules. All the rest follow phonetic patterns so there’s no need to memorize each individually.

@gailcalled – This helps you?

Brute animals are strictly dry:
They sinless live and swiftly die.
But sinful, gin-full, beer soaked men
Survive for threescore years and ten

Doggerel is always fun
But doesn’t mean that anyone
Can just add “full” to any word
And make it sense-full, not absurd.

But you just __did!__, @gailcalled

Note that “sense-full”
Is self-referenceful.

Thanks everyone.

When do we add just y to the word to make an adverb? Isn’t there a rule: When there is 2 lls just add y, and when it has one l add ly. Do you have examples?

You add -ly to make an adverb. Even when it ends in -l, as in hopefully; you are adding -ly. I don;t know of any circumstance where you just add a -y.

There is Full.

By the way my title OP sounds like I’m referring to meaning, but I wasn’t. I was referring to the spelling.